charging an "airport fee toll" to customers even though drivers were not paying the airport

District attorneys are seeking an injunction against Uber that could see its drivers temporarily banned from the two cities.

By contrast, rival firm Lyft has reached a settlement with the same district attorneys. It will submit its app to the authorities for accuracy checks as well as seeking authorisation to operate in airports.

It will also pay civil penalties of $500,000, half of which will be paid within 30 days while the rest could be waived if the firm complies with the terms of the injunction.

Badges issued

Other US cities have also begun legal action against Uber.

In Portland, Oregon, the firm is being sued for failing to seek consent on how it would be regulated.

Meanwhile, Max Tyler, a Colorado state representative, has questioned how it vets drivers, alleging that the firm does not run an FBI background check, something which other taxi drivers have to have.

Its process of recruiting new drivers is also being looked at by authorities in New Delhi after a driver, who was previously accused of raping a female passenger in 2011, was cleared to drive for Uber.

The driver has been arrested for another alleged rape and appeared in court on Monday. He had obtained a reference from the Delhi Police, but police spokesman Rajan Bhagat told Reuters that the certificate appeared to be fake.

Indian police also questioned an Uber executive about the checks run on drivers. Police said that Uber's drivers did not have the special badges that it issues to taxi drivers proving that they have cleared background checks.

They said that Uber and similar services that operate online platforms linking drivers with customers are registered in India as technology businesses rather than transport companies.

Huge expansion

In a statement Uber said it would work with the Indian government to "establish clear background checks currently absent in their commercial transportation licensing programmes".

It added that it would also partner with women's safety groups and "invest in technology advances to help make New Delhi a safer city for women".

Uber defended the way it checked drivers, saying it was a responsibility it took seriously. According to the firm, it is on track to complete more than two million background checks this year.

The company, which now operates in 52 countries, was recently valued at $40bn after an investment by venture capitalists.

But since its launch the business, which uses a smartphone app to connect riders with drivers, has proved hugely controversial. In Europe, registered taxi drivers' unions have staged strikes and protests against what they see as light regulation of Uber and similar services.

Uber's business practices have also been questioned and doubts raised over whether its tracking system breaks data protection laws.